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From:   Dejin Zheng <zhengdejin5@gmail.com>
To:     balbi@kernel.org, gregkh@linuxfoundation.org,
        linux-usb@vger.kernel.org
Cc:     linux-kernel@vger.kernel.org, Dejin Zheng <zhengdejin5@gmail.com>
Subject: [PATCH v1] usb: dwc3: core: fix a issue about clear connect state
Date:   Sun, 18 Oct 2020 21:47:34 +0800
Message-Id: <20201018134734.10406-1-zhengdejin5@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

According to Synopsys Programming Guide chapter 2.2 Register Resets,
it cannot reset the DCTL register by set DCTL.CSFTRST for Core Soft Reset,
if DWC3 controller as a slave device and stay connected with a usb host,
then, reboot linux, it will fail to reinitialize dwc3 as a slave device
when the DWC3 controller did not power off. because the connection status
is incorrect, so we also need clear DCTL.RUN_STOP bit for disable connect
when do core soft reset.

Fixes: f59dcab176293b6 ("usb: dwc3: core: improve reset sequence")
Signed-off-by: Dejin Zheng <zhengdejin5@gmail.com>
---
 drivers/usb/dwc3/core.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 2eb34c8b4065..239636c454c2 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -256,6 +256,7 @@ static int dwc3_core_soft_reset(struct dwc3 *dwc)
 
 	reg = dwc3_readl(dwc->regs, DWC3_DCTL);
 	reg |= DWC3_DCTL_CSFTRST;
+	reg &= ~DWC3_DCTL_RUN_STOP;
 	dwc3_writel(dwc->regs, DWC3_DCTL, reg);
 
 	/*
-- 
2.25.0